School Projects
Time Domain Electromagnetic Surveying System
Description
The project was done through the capstone program, we worked as a team of 5 to design
the pulse generation hardware to be used on a full scale surveying system. The hardware
was split into two stages, the charging hardware to take a 28V input and boost the voltage
to charge capacitors up to 1000V and the H-Bridge hardware which utilizes IGBTs to control
a 500A current pulse through an inductor coil suspended below a helicopter. We also wrote
code for STM32 microcontrollers to implement control loops for both the charging circuitry
and the pulse generation. Control of the H-Bridge allows us to evenly spread the load
between the IGBTs to avoid damaging components as well as being able to add more
energy into the system to maintain the 500A pulse despite losses through the coil.
Contributions
I was in charge of charging circuitry for this project. I researched and simulated available
boost topologies and ended up selecting a flyback converter due to the high gain potential
and efficiency, with the only limit to maximum voltage being component ratings and charge
time. The converter operates by charging up the primary side of a transformer and then
disconnecting the primary to charge the capacitors on the secondary side.